The Salmon Cannon
By Emily Tripp
Salmon are born in fresh water, travel hundreds of kilometers to the ocean for most of their adult lives, and then navigate all the way back to the exact same spot they were born to spawn. But artificial water constructions, like dams, have made their journeys difficult and sometimes deadly.
Fish ladders have been used as a successful method to help salmon and other migratory fish make their way back home without getting disoriented, injured, or killed in turbines, but now there’s an even better solution: the salmon cannon.
Created by Wooshh Innovations, the salmon cannon transports fish in a soft fabric tube at speeds of five to 10 meters per second (11-22 mph). This method is gentle and keeps the fish out of water for only a few seconds.
The cannon has been tested at multiple locations in Washington state. The team manually fed fish into the tubes during some trials, and let the fish swim into it themselves in others.
The successful trials of salmon cannon come at a particularly good time, as a new study revealed that sockeye salmon that have to sprint to spawning grounds through fast-moving waters have an increased mortality rate.
When swimming through rapids or downstream dams, salmon must swim extra fast, using a behavior known as “burst swimming,” which requires extra oxygen and energy and can lead to cardiac collapse or heart attacks. The researchers found that if salmon chose to bust swim for long periods, they were more likely to die on their way to their spawning grounds than fish that swam slower.
“Our work demonstrates how important it is for salmon to have easy access around obstacles in the river,” lead author and University of British Columbia research biologist Nicholas Burnett explained.
Emily Tripp is the publisher and editor of MarineScienceToday.com, an online magazine about what's in, on, and around the oceans. She holds marine science and biology degrees from the University of Miami's Rosenstiel School of Marine and Atmospheric Science.